[talk-au] Snapping Major regional roads to GPS traces

[Sebastian S.]

Thanks Simon for bringing this back to best practices.

Is there a good how to for this alignment of aerial imagery? 
I always struggled with the JOSM interface. I also thought that this was something stored locally for the JOSM instance only.


On 16 May 2021 3:56:59 am AEST, Simon Poole <simon at poole.ch> wrote:
>IMHO this is not what you should be doing. You should be using the GPS 
>traces and possible other data to adjust the aerial/sat imagery (and 
>then storing the offsets in the imagery offset DB).
>
>The reason for this is simple, GPS traces are notoriously bad at 
>capturing the actual topology of roads (that is junctions etc) and if 
>they are available you will nearly always (except if they are very out 
>of date, or very hilly/mountainous areas and bad orthorectification)  
>want to derive the geometry from the aerial imagery.
>
>Simon
>
>Am 14.05.2021 um 08:23 schrieb Bob Cameron:
>> Just checking if this is an okay thing to do. ie moving a major road 
>> so it is centred on GPS traces - assuming there enough data for 
>> accuracy (eg bidirectional, multi trace etc)
>>
>> The traces are probably more accurate than overhead imagery.
>>
>> Other features placed relative to roads will also need moving?
>>
>> Reason I ask is a concern that there may be an automated process that
>
>> adjusts existing roads.
>>
>> Tnx
>>
>>
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